Expenditures for dental services are increasing rapidly as more Americans obtain private or publicly funded dental insurance. The existing utilization review (UR) system used by third parties (pretreatment review) has only a limited effect in controlling the cost and quality of dental services. The purpose of this study is to evaluate the cost-effectiveness of a new UR system based on information derived from practice profiles. Claim data on 1,000 general dentists will be obtained from Blue Cross and Blue Shield of Greater New York (BC/BSGNY( (N equals 500) and Aetna Life and Casualty (N equals 500). Practice profiles, standardized for patient and insurance plan characteristics, will be used to identify dentists who are likely over-utilizers. An attempt will be made to change the practice patterns of these dentists (c. 145) through two types of interventions: 1) personal contacts informing them of their unusual practice patterns and 2) providing dental consultants specific instructions on the types of abuses to look for when reviewing claims from these dentists. For each intervention there are three levels of application which are employed sequentially, depending on the dentist's response to the previous intervention. The effectiveness of the new UR system will be evaluated in terms of operational costs, savings, and provider and patient acceptance and compared with the existing pretreatment review system. The new IU system has the potential to significantly reduce expenditures for dental care through better control of over-utilization. With the support of BC/BSGNY and Aetna, dissemination of the new UR system to other private and public third parties and regulatory agencies should proceed rapidly.